Not Applicable
Not Applicable
1. Field of the Invention
The present invention relates generally to accessories used with plows (e.g., snow plows) and graders. More particularly, the present invention concerns a device for handling replaceable plates, such as cutting edges and wear plates, used on the blades of plows and graders. The present invention also concerns the improved method of installing the replaceable plates.
2. Discussion of Prior Art
The blade of a plow or grader is typically provided with at least one replaceable plate for improving the cutting and/or plowing action of the blade and for increasing the life span of the blade. It is common to utilize a dual plate arrangement, which often includes a cutting edge secured against the lower margin of the front face of the blade and a wear plate secured over the cutting edge. The cutting edge projects downwardly below the lower margin of the blade and is customarily formed of a hard material, such as tungsten carbide. The wear plate is designed to cooperate with the cutting edge in improving blade operation and durability. Particularly, the wear plate and cutting edge are preferably coextensive, with the wear plate being superimposed over the cutting edge. The wear plate is preferably formed of a stronger, more durable material (e.g., standard carbon steel) than the cutting edge. That is to say, the cutting edge is typically formed of a brittle albeit hard material, and the wear plate is consequently designed to absorb the impact loads created as the blade encounters objects, such as rocks or other debris located on a roadway.
It will be appreciated that replacement plates extend across the entire blade and are consequently relatively long, even when divided into several sections arranged end-to-end across the front of the blade. For example, a typical plow blade and the replacement plates used thereon will be approximately twelve feet long (measured from side to side). The plates are consequently unwieldy and heavy. Moreover, replacement of the plates traditionally involves two workers manually holding the plate off of the ground and moving the plate until the attachment holes in the plate align with the corresponding attachment holes defined in the blade, while a third worker inserts bolts through the aligned attachment holes. It will also be appreciated that conventional replacement plates will often weigh in excess of one hundred pounds. Thus, the conventional system for replacing the plates used on the blade of a grader or plow is laborious, difficult and expensive.
Responsive to these and other problems, an important object of the present invention is to provide a system for simplifying and facilitating the replacement of the plates used on the blade of a plow or grader. It is also important object of the present invention to provide a device for assisting the worker with manipulation of the plates during installation and removal. Another important object of the present invention is to make the device inexpensive and simple in construction, yet sufficiently durable to withstand the rigorous operating conditions encountered during blade replacement. Yet another object of the present invention is to provide a system that permits the plates to be replaced by only one worker, without requiring the worker to manually hold the plates off of the ground during replacement.
In accordance with these and other objects evident from the following description of the preferred embodiment, the present invention concerns a device in the form of a cart for handling the replaceable plates used on the blade of a plow or grader. The cart includes a wheeled frame and a plate holder supported on the frame for up and down movement relative to the ground. The plate holder is designed to support the plate in an orientation generally corresponding to the front face of the blade. This typically involves supporting the plate in an upright orientation so that the plate may be placed against the generally upright front face of the blade. In some cases, the plate may be oriented at a slight angle relative to vertical to correspond with the orientation and/or the curvature of the front face of the blade.
The cart preferably includes a parallelogram linkage for supporting the plate holder on the frame, with the linkage maintaining the plate holder, and thereby the plate or plates supported thereon, in a single orientation as the holder is raised and lowered. An actuator may be connected between the frame and linkage for effecting raising and lowering of the plate holder. This is particularly useful when the cart is being used to install large, heavy plates. The cart may also be provided with a tongue that facilitates movement of the cart into the desired locations, especially in low clearance situations. The frame of the cart is preferably supported on caster wheel assemblies, and the tongue may be attached to the frame in several different locations to improve maneuverability of the cart.
The present invention also concerns the improved method of installing the replaceable plates. This method permits just one worker to install the plates, without having to manually hoist the plates during installation. Particularly, the installation method involves the steps of supporting at least one plate on a mobile cart and aligning the attachment holes defined in the at least one plate with the corresponding attachment holes defined in the blade. The plate is preferably supported on a height-adjustable holder carried on the frame so that the height of the plate may be adjusted during the step of aligning the attachment holes. Of course, alignment of the attachment holes may also involve moving the cart into proximity with the blade.